that looks amazing. i want to try making something like it now =D

Yeah it's amazing. I wish it was finished. I wish, however, that that last part in the screenie was made possible to beat, though.

More like 10 times worse than Ghosts 'n' Goblins, starting in that one room in the screenshot. But it is possible that it is the last room and that the author made it close to impossible to prevent going further and getting a RAM clear or something.

It does not look so bad.

Oh I did not notice the floor was slippy

I think the author made movement like that just so that physics remains as realistic as possible. However, it is a bit too slippery I think for such small maps and precise jumping requirements and it would work better for a game like Sonic. Had this been finished with walking physics at least similar to SMB1 (where it's far more responsive) it would probably have a reasonable difficulty level. Right now, if you barely tap the directional keys you don't even move at all and if you hold down the key for a while longer you can't stop fast enough.

It's a great game so far in general and if it was easier and I could notice a lot of more rooms, I could have made  a news.

I doubt it, sadly, because in his readme he mentions that he's done with calc programming and has since moved on to more powerful platforms. From what I remember from the readme too, I think it has been a long while since he actually worked on that calc game.